Writing regular expression to validate Alphanumeric string

Can any one helping  to writing call to validate Alphanumeric string

https://community.telligent.com/community/8/w/api-documentation/45559/core-v2-utility-widget-extension

#set($input ="00034001182B6091")

#set( $pattern = "[a-zA-Z0-9]+")

#set($booleanResponse = $core_v2_utility.IsMatch($input, $pattern, "%{RegexOptions = $regexOptionsArg}"))